Q.What to Do With Struggling Hibiscus
In southern England I have 3 hibiscus plants. The blue one is fine and thriving, but the 2 maroon coloured ones do not flower. The flower head starts to develop but stays very tight and very small. These two are in different parts of the garden. The flower petals stay so tight and small that they do not come out at all. Please help!
Certified GKH Gardening Expert
It sounds like you may have thrips. They are very small pests that attack the base of flower buds and cause them to fall off before they open. This article will help:
https://www.gardeningknowhow.com/plant-problems/pests/insects/controlling-thrips.htm
There is also a possibility that they are not getting enough water. The plant will drop its flower buds if it is underwatered. It would not hurt to increase water to the plants for a bit and see if that helps.